import java.util.Scanner;

/**
 * Created by JiaJia on 2019/4/10 0010.
 */
public class WeiZhong001 {

    public static void main(String[] args) {
        Scanner sc =new Scanner(System.in);
        while (sc.hasNext()){
            int num = sc.nextInt();
            int n = sc.nextInt();
            System.out.println(calSum(num,n));

        }

        sc.close();
    }

    private static String calSum(int num,int n){
        double sum =num;


        while (n-->1){
            double y =Math.sqrt(num);
            sum+=y;
        }

        String str = String.format("%.2f",sum);
        return str;

    }
}